[sdiy] Back on the list - Guitar synth

[Peter Snow]

Hi Mark,

Welcome back to the list. I have been following your recent posts on the Yahoo
MIDI guitar list and it revived my interest in the GR300 which is lurking in my
basement somewhere. Do you have schems of your various mods?  Are they available
online?

Thanks,

Peter

Mark Smart wrote:
> 
> Hi all.
> I just rejoined the list after being off of it for a long time.
> 
> In the last few weeks I have had another bout of "guitar synth fever" and am
> working on my analog guitar synth board again. This is an ongoing project I
> started many years ago and work on about once a year or so. The whole thing
> is based around the old, clunky amazing Roland GR-300 with its blindingly
> fast tracking. I decided to start trying to modify it to make more sounds,
> so I have developed circuits to change its unusual sawtooth waves into pulse
> waves (this is just an AD633 analog multiplier chip and a comparator) , and
> to translate its linear control voltages (which are proportional to the
> guitar string's cycle time) into 1 volt/octave CV's to interface with other
> analog modules. I just got all six log converters wired up for the first
> time yesterday. My log converter is based on the one from Electronotes
> AN-114, but I used a 3046 and added a temperature regulator stolen from Rick
> Jansen's Moog filter circuit (thanks Rick!). This works great because the
> period-to-voltage converter described in AN-114 is very similar to the
> GR-300's.
> 
> I now have this mad vision of wiring my GR-300-on-a-box up to a large MOTM
> modular to make a polyphonic synth with filters for each string and pulse
> wave capability.
> 
> Mwahahahaa....
> 
> I am interested from hearing from others doing guitar stuff. Also, if there
> is a searchable archive for the list, where is it? That will keep me from
> asking questions people have already answered (except for "Where is the
> searchable archive?"). Thanks.
> 
> Mark Smart